Chronic Neuropathic Pain Syndromes Research Articles

Ultrasound guided versus fluroscopic guided pulsed radiofrequency therapy of the stellate ganglion in neuropathic pain: A prospective controlled comparative study

ObjectiveTo assess the efficacy and safety of fluoroscopic–guided versus ultrasound (US)-guided techniques for pulsed radiofrequency (RF) therapy of stellate ganglion for refractory neuropathic pain syndromes. Methods40 patients with severe chronic neuropathic pain syndromes, Visual Analogue Scale (VAS) score > 7, with poor response to medical treatment were randomly integrated into 2 groups: Group (F): (20 patients) in whom pulsed R.F. therapy is done under fluoroscopy, group (U): (20 patients) in whom pulsed R.F. therapy is done under US guidance. ResultsThe current study revealed that there is significant reduction of VAS, and of the medical treatment consumption after the block as compared with pre block values, there is no statistically significant difference between the guidance techniques of RF treatment in pain relief. However, the procedure time was significantly lower in U group. ConclusionPulsed R.F. blockade of the stellate ganglion in patients with refractory neuropathic pain syndromes can be done safely and efficiently under the guidance of either ultrasound or fluoroscopy. Both radiological techniques provide similar satisfactory guidance without significant complications.

The Current Treatment and Prevention of Post Herpetic Neuralgia

Post herpetic neuralgia (PHN) is a chronic neuropathic pain syndrome in the area of the herpes zoster (HZ) rash, persisting after the cutaneous lesions have subsided. Despite numerous treatment advances, many patients remain refractory to the current therapies and continue to have pain, physical, economical and psychological distress. In this review, we will focus on the current treatment and prevention of PHN.

Small fiber neuropathy

Despite the fact that small fiber neuropathy (SFN) has already been studied for 30 years, it remains one of the most mysterious diseases that are extremely difficult to diagnose and cure. The prevalence of SFN is 52.95 per 100,000 population; diabetes mellitus is considered to be the most frequent cause of this disease. Chronic neuropathic pain syndrome, temperature sensation abnormalities, and vegetative disorders develop as a result of damage to fine myelinated Аδ- and unmyelinated C fibers. The disease mainly spreads in the upward direction: from feet to the proximal body parts and arms; primary axonal damage takes place. Although SFN is believed to be one of the most “benign” neuropathy types as it does not affect the large sensory and motor fibers, it significantly decreases patients’ quality of life.

Methadone

Methadone

The Synergistic Effect of Intrathecally Administered Dexmedetomidine and Ketorolac on Mechanical Allodynia in Rats with Spinal Nerve Ligation

Objectives This research was carried out to identify the synergistic effect of dexmedetomidine and ketorolac on neuropathic pain alleviation. Methods The anti-allodynic effect of intrathecal dexmedetomidine and ketorolac was investigated in rats after L5 spinal nerve ligation (SNL). Mechanical allodynia was assessed using Von Frey filaments. Every day for 3 consecutive days, beginning on the 10th day after SNL, behavioral tests were carried out at 1, 2, and 4 hr after drug injection. Results Significant increases in ipsilateral paw withdrawal thresholds (PWTs) were observed 1, 2, and 4 hr after drug injection in the groups of rats which received intrathecal injection of either dexmedetomidine (group D) or ketorolac (group K), compared to group S (P< 0.05). And group DK, which received simultaneous intrathecal injection of both dexmedetomidine and ketorolac, showed statistically significantly higher ipsilateral PWTs than groups D and K, which received only one of them (P< 0.05). Conclusions The results of this research demonstrated the anti-allodynic effect of dexmedetomidine and ketorolac on neuropathic pain induced by SNL in rats. They also suggest that synergistic analgesia can be induced by the simultaneous injection of dexmedetomidine and ketorolac, and that combination therapy is an effective approach to treating chronic neuropathic pain syndrome.

5% Lidocaine-medicated plaster for the treatment of chronic peripheral neuropathic pain: complex regional pain syndrome and other neuropathic conditions.

ObjectivesChronic neuropathic pain and chronic complex regional pain syndrome (CRPS), in particular, are debilitating and difficult-to-treat conditions that have a strong impact on patient’s quality of life. The aim of this study was to evaluate the effectiveness of 5% lidocaine-medicated plaster as add-on therapy in patients with chronic peripheral neuropathic pain conditions, including CRPS.Patients and methodsThis was a single-center, prospective, observational study set in a specialized pain unit of a tertiary hospital in Spain. A total of 56 patients with long-standing peripheral neuropathic pain, ten of them with CRPS, received 5% lidocaine-medicated plaster as add-on analgesic therapy for 6 months.ResultsAfter 6 months of treatment, a ≥50% reduction in pain intensity was attained by 75% of patients, as measured by numeric rating scale (NRS) for pain. The average NRS score was reduced by 61% (4.7 points), from a baseline mean score of 7.8 to an end point mean score of 3.1. Marked improvements were also observed in the CRPS group: six out of ten patients achieved a ≥50% reduction in NRS score, and the average NRS score for patients with CRPS was reduced by 51% (4.0 points), from a baseline mean score of 7.9 to an end point mean score of 3.9. The improvements in pain intensity were partially translated into a decrease in disability index and in anxiety levels.Conclusion5% Lidocaine-medicated plaster may be useful as add-on therapy for a number of peripheral neuropathic pain conditions, including CRPS.

Clinical Significance of Invasive Motor Cortex Stimulation for Trigeminal Facial Neuropathic Pain Syndromes

Invasive neuromodulation of the cortical surface for various chronic pain syndromes has been performed for >20 years. The significance of motor cortex stimulation (MCS) in chronic trigeminal neuropathic pain (TNP) syndromes remains unclear. Different techniques are performed worldwide in regard to operative procedure, stimulation parameters, test trials, and implanted materials. To present the clinical experiences of a single center with MCS, surgical approach, complications, and follow-up as a prospective, noncontrolled clinical trial. The implantation of epidural leads over the motor cortex was performed via a burr hole technique with neuronavigation and intraoperative neurostimulation. Special focus was placed on a standardized test trial with an external stimulation device and the implementation of a double-blinded or placebo test phase to identify false-positive responders. A total of 36 patients with TNP were operated on, and MCS was performed. In 26 of the 36 patients (72%), a significant pain reduction from a mean of 8.11 to 4.58 (on the visual analog scale) during the test trial was achieved (P < .05). Six patients were identified as false-positive responders (17%). At the last available follow-up of 26 patients (mean, 5.6 years), active MCS led to a significant pain reduction compared with the preoperative pain ratings (mean visual analog scale score, 5.01; P < .05). MCS is an additional therapeutic option for patients with refractory chronic TNP, and significant long-term pain suppression can be achieved. Placebo or double-blinded testing is mandatory. MCS, motor cortex stimulationNRS, numeric pain rating scaleTNP, trigeminal neuropathic or deafferentation painVAS, visual analog scale.

Characteristics of Ocular Pain Complaints in Patients With Idiopathic Dry Eye Symptoms.

The purpose of this study was to examine the severity and quality of ocular pain complaints in patients with dry eye symptoms. Subjects with clinically relevant dry eye symptoms (dryness, discomfort, tearing) of unknown origin seen in the Miami Veterans Affairs eye clinic were administered questionnaires for dry eye symptoms and ocular pain and underwent a standardized ocular examination. Qualities and severity ratings of ocular pain in subjects with idiopathic dry eye were compared with similar measures from published data in other chronic pain populations. The study sample consisted of 154 subjects, of which 91% were men and ranged in age from 27 to 89 (mean age=61). Fifty-three percent of participants reported an average ocular pain of at least moderate intensity (numerical rating scale≥4), with specific characteristics (i.e., "burning" spontaneous pain) reported at frequencies comparable to prevalent chronic neuropathic pain syndromes as reported in the literature. Significant correlations were found between ocular pain metrics and dry eye symptom severity scores (r=0.57-0.66). Dry eye signs, however, did not generally correlate with ocular pain severity. A significant proportion of subjects with idiopathic dry eye symptoms reported moderate or greater ocular pain intensity, with most endorsing descriptors commonly used by patients with nonocular neuropathic pain conditions. Identifying subgroups of dry eye patients based on the presence and characteristics of ocular pain complaints may improve dry eye subclassification and better individualize treatment strategies.

Peripheral nerve field stimulation for chronic neuropathic pain: a single institution experience.

Peripheral nerve field stimulation (PNFS) is a novel neurosurgical procedure consisting of implantation of subcutaneous leads in specific painful areas in different types of painful, drug-resistant syndromes. The objective of this study was to evaluate the efficacy of PNFS in several patients affected by different chronic neuropathic pain syndromes, along with its risks, limits and possible correlation between the results achieved and the patients' main symptoms. Twenty-two patients affected by different types of chronic neuropathic pain were submitted to PNFS at the Department of Neurosurgery of the Istituto Neurologico "C. Besta" in Milan between July 2009 and July 2013. The visual analog scale (VAS) and variations in the use of analgesic drugs, along with complications, were considered to assess results. In 59% of our patients, an average pain reduction of 5.50 points on the visual analog scale was observed (average pre-implant score 8.86 and average post-implant score 3.36). These patients reduced their analgesic drug use after PNFS. We observed no early or long-term complications after our last follow-up evaluation. PNFS can be considered an effective and safe option to treat carefully selected, drug-resistant and chronic neuropathic pain patients; the reversibility of the procedure and its lack, at least in our hands, of long-term complications may contribute to wider use of this procedure.

Cortical neurostimulation for neuropathic pain

The treatment of neuropathic pain by neuromodulation is an objective for more than 40 years in modern clinical practice. With respect to spinal cord and deep brain structures, the cerebral cortex is the most recently evaluated target of invasive neuromodulation therapy for pain. In the early 90s, the first successes of invasive epidural motor cortex stimulation (EMCS) were published. A few years later was developed repetitive transcranial magnetic stimulation (rTMS), a noninvasive stimulation technique. Then, electrical transcranial stimulation returned valid and is currently in full development, with transcranial direct current stimulation (tDCS). Regarding transcranial approaches, the main studied and validated target was still the motor cortex, but other cortical targets are under investigation. The mechanisms of action of these techniques share similarities, especially between EMCS and rTMS, but they also have differences that could justify specific indications and applications. It is therefore important to know the principles and to assess the merit of these techniques on the basis of a rigorous assessment of the results, to avoid fad. Various types of chronic neuropathic pain syndromes can be significantly relieved by EMCS or repeated daily sessions of high-frequency (5-20 Hz) rTMS or anodal tDCS over weeks, at least when pain is lateralized and stimulation is applied to the motor cortex contralateral to pain side. However, cortical stimulation therapy remains to be optimized, especially by improving EMCS electrode design, rTMS targeting, or tDCS montage, to reduce the rate of nonresponders, who do not experience clinically relevant effects of these techniques.

Pain Syndromes Other Than Headache

Pain is experienced within a complex biologic, emotional, psychological, and social context that may defy physical examination, diagnostic procedures, and laboratory tests. This chapter aims to empower internists to improve their medical practices in pain management. It provides a scientific background that covers nociception and how sensory processing occurs at multiple levels in the body. Clinical assessment is detailed, as well as diagnostic categories that include mixed or uncertain chronic pain syndromes (back pain, fibromyalgia, postamputation pain, pain from cancer and bone) and neuropathic pain syndromes (polyneuropathy, mononeuropathy multiplex, ganglionopathy, genetic disorders, focal and regional syndromes). Treatment of chronic pain can be surgical or interventional. Pharmacologic treatment for acute and chronic nociceptive pain includes special considerations for geriatric and terminal patients. For treatment of neuropathic pain, medications are the major component. One tables lists iatrogenic nerve injuries that can cause posttraumatic neuralgia and complex regional pain syndrome. Other tables detail stepwise pharmacologic management of neuropathic pain and cite recommendations on opioid use from the Centers for Disease Control and Prevention. One figure illustrates how pain transducers monitor and influence tissue conditions. Other figures show sensory processing in the spinal cord dorsal horn, physical findings in the feet of patients with bilateral foot pain from small-fiber polyneuropathy, illustrate how examination can identify specific nerve injuries causing chronic pain, and provide classification of chronic pain syndromes. This chapter contains 82 references.

Pain Syndromes Other Than Headache

Pain is experienced within a complex biologic, emotional, psychological, and social context that may defy physical examination, diagnostic procedures, and laboratory tests. This chapter aims to empower internists to improve their medical practices in pain management. It provides a scientific background that covers nociception and how sensory processing occurs at multiple levels in the body. Clinical assessment is detailed, as well as diagnostic categories that include mixed or uncertain chronic pain syndromes (back pain, fibromyalgia, postamputation pain, pain from cancer and bone) and neuropathic pain syndromes (polyneuropathy, mononeuropathy multiplex, ganglionopathy, genetic disorders, focal and regional syndromes). Treatment of chronic pain can be surgical or interventional. Pharmacologic treatment for acute and chronic nociceptive pain includes special considerations for geriatric and terminal patients. For treatment of neuropathic pain, medications are the major component. One tables lists iatrogenic nerve injuries that can cause posttraumatic neuralgia and complex regional pain syndrome. Other tables detail stepwise pharmacologic management of neuropathic pain and cite recommendations on opioid use from the Centers for Disease Control and Prevention. One figure illustrates how pain transducers monitor and influence tissue conditions. Other figures show sensory processing in the spinal cord dorsal horn, physical findings in the feet of patients with bilateral foot pain from small-fiber polyneuropathy, illustrate how examination can identify specific nerve injuries causing chronic pain, and provide classification of chronic pain syndromes. This chapter contains 82 references.

Off-label use of duloxetine for pediatric neuropathic pain

Abstract Introduction Duloxetine, a serotonin-norepinephrine reuptake inhibitor, has been used successfully for adults for the management of neuropathic pain syndromes. Pediatric data are needed because inadequate neuropathic pain management in children and adolescents results in lower psychosocial functioning, delayed development, and decreased quality of life. We aim to describe a case series on the use of duloxetine for the management of symptoms associated with chronic neuropathic pain syndromes in a pediatric population. Methods Data were collected in a naturalistic, consecutive, case report format, from a pediatric pain management clinic for children prescribed duloxetine for analgesia for a variety of neuropathic-type pain conditions. Follow-up data, including self-report of pain, and type and frequency of adverse reactions, were collected to describe the efficacy and safety of duloxetine. Results Duloxetine was prescribed for the management of self-reported average pain scores of greater than 5 out of 10 on the Faces Pain Scale–Revised for pain that was resistant to other medications. Each of these patients had comorbid psychiatric diagnoses. Reduction in pain following duloxetine therapy was not universal, and all patients discontinued duloxetine therapy prematurely because of adverse effects. Conclusion Further evidence is needed to demonstrate the efficacy and safety of duloxetine for use in pediatric populations with neuropathic components to their pain. Based on our experience, we suggest considering its use only after failure of other agents. The best management of a pediatric patient's pain condition is likely accomplished through a combination of pharmacotherapy and nonpharmacotherapy interventions.

Spinal Cord Epidurial Stimulation for Neuropathic Pain Syndrome Treatment of Disseminated Sclerosis Patient

DOI: 10.17691/stm2015.7.2.24 Received february 13, 2015I.N. Morozov, MD, DSc, Senior Researcher, Consultation and Rehabilitation Department;A.I. Ushakov, Researcher, Department of the NeurosurgicalPrivolzhsky federal Research Medical Center, Ministry of Health of the Russian federation, 18 Verkhne-Volzhskaya naberezhnaya St., Nizhny Novgorod, 603155, Russian federationThe paper describes successful treatment case of medicamentally-resitant chronic neuropathic pain syndrome of 63 year old patient with cerebro-spinal form of disseminated sclerosis. for the purpose of pain correction the patient received percutaneous implantation of epidural electrodes and Medtronic pulse generator (uSA) which allowed for pain reduction by 50%, refusal of semi-narcotic analgesics taking and revert to habitual everyday activity.Key words: neuropathic pain; neuromodulation; disseminated sclerosis.For contacts: Morozov Ivan Nicolaevich, ivanmorozov@list.ru

Anti-allodynic Efficacy of NMDA Antagonist Peptide and Noradrenaline Alone and in Combination in Rodent Neuropathic Pain Model

BackgroundThe present experiment was conducted to identify the cooperative effect of serine histogranin (SHG) and noradrenaline in alleviating peripheral neuropathic pain.MethodsChronic constriction injury of the right sciatic nerve was used to induce chronic neuropathic pain. For drug delivery, a PE10 tube was inserted into the subarachnoid space. Acetone drops and a 44℃ water bath were used to evaluate the cold and heat allodynia, respectively. Placing and grasping reflexes were used to assess the locomotor system.ResultsSHG at 0.5 and 1 µg significantly (P < 0.05) decreased the thermal allodynia. The cold allodynia was also significantly reduced by intrathecal injections of 0.5 (P < 0.05) and 1 µg (P < 0.001) of SHG. 1 µg of noradrenaline, but not 0.5 µg, significantly alleviated the cold (P < 0.01) and thermal (P < 0.05) allodynia. The ameliorating effect of noradrenaline or SHG disappeared when the two compounds were administrated in equal concentrations. A significant difference (P < 0.01 in the acetone and P < 0.05 in the heat) was observed in the groups under equal doses of the two compounds, with a lower effectiveness of the combination therapy.ConclusionsOur findings suggest that the simultaneous administrations of noradrenaline and SHG do not result in synergistic analgesia, and combination therapy may not be a good approach to the treatment of chronic neuropathic pain syndrome.

Results of motor cortex stimulation in the treatment of chronic pain syndromes

The article is aimed to demonstrate our experience in motor cortex stimulation (MCS) in patients with chronic neuropathic pain syndromes, assess the clinical efficacy of the technique in short-term and long-term follow-up, and analyze potential predictors of the MCS efficacy. Twenty patients were implanted with MCS electrodes at the Burdenko Neurosurgical Institute in the period between 2004 and 2014. The mean age of patients was 52 years (26 to 74 years). The patients suffered from neuropathic pain syndromes of different genesis (post-stroke, multiple sclerosis, atypical facial pain, phantom limb pain, brachial plexus injury, spinal cord injury, complex regional pain syndrome I). All patients underwent neurological examination with verification of neuropathic pain (DN4, Pain Detect, LANSS). The pain intensity and its effect on quality of life were assessed before operation and during follow-up according to 10-point visual-analog scales (modified Brief Pain Inventory). Before surgery, all patients underwent several repetitive transcranial magnetic stimulation (rTMS) sessions. After implantation of epidural electrodes, test MCS was performed. Test stimulation was positive in 19 (95%) patients. All these patients were implanted with a chronic MCS system. The mean follow-up was 49.3 months (from 3 to 96 months). In short-term follow-up (fist 6 months), a positive result of MCS was observed in 17 patients, and a reduction in the pain intensity ranged from 37.5% to 90%. In long-term follow up (from 12 to 96 months), 14 patients had positive MCS RESULTS: and a reduction in the pain intensity amounted to 25% to 60%. All patients with positive MCS results received significantly decreased doses of opioids and tramadol. Two patients developed infectious complications, but there was no neurological deficit. Analysis of the factors affecting the efficacy of motor cortex stimulation did not reveal a statistically significant effect of rTMS and the presence and intensity of motor deficit. Chronic epidural MCS is an effective and safety method for the treatment of some chronic neurogenic medically-refractory pain syndromes. Further research is necessary to specify the patient selection criteria and the MCS efficacy predictors.

P1003: Differential gene expression in two different experimental models of neuropathic pain

P1003: Differential gene expression in two different experimental models of neuropathic pain

Study of Nociceptive Flexion Reflex in Healthy Subjects and Patients with Chronic Neuropathic Pain Syndrome

Nociceptive flexion reflex was measured in healthy subjects and patients with chronic neuropathic pain (diabetic distal symmetric sensorimotor polyneuropathy). The study of nociceptive flexion reflex revealed reduction of subjective pain threshold and reflex threshold in patients compared with healthy persons reflecting deficit of descending antinociceptive influences in the CNS.

Neuropathic pain: role of inflammation, immune response, and ion channel activity in central injury mechanisms.

Neuropathic pain (NP) is a significant and disabling clinical problem with very few therapeutic treatment options available. A major priority is to identify the molecular mechanisms responsible for NP. Although many seemingly relevant pathways have been identified, more research is needed before effective clinical interventions can be produced. Initial insults to the nervous system, such as spinal cord injury (SCI), are often compounded by secondary mechanisms such as inflammation, the immune response, and the changing expression of receptors and ion channels. The consequences of these secondary effects myriad and compound those elicited by the primary injury. Chronic NP syndromes following SCI can greatly complicate the clinical treatment of the primary injury and result in high comorbidity. In this review, we will describe physiological outcomes associated with SCI along with some of the mechanisms known to contribute to chronic NP development.

Magnetic Resonance Imaging-Guided Perineural Therapy as a Treatment Option in Young Adults with Pudendal Nerve Entrapment Syndrome

pudendal neuralgia is a rare chronic neuropathic pain syn-drome in the perineal region. It can be unilateral or bilate-ral and is described as superficial pain, burning sensation or paraesthesia in the anatomical territory of the pudendal nerve which is typically worsened by sitting and barely affects nocturnal sleeping. The incidence is estimated to be 1/100,000 but the etiology and pathogenesis remain incom-pletely understood with hypotheses ranging from mechani-cal nerve injury caused by entrapment (pelvic floor muscle spasm, pressure from surrounding ligaments or scar tissue after trauma, surgery or childbirth) to viral infections or immunological processes [1].